Rifampicin initially increases the trough levels of
caspofungin by 170%, but after 2 weeks the trough levels of
caspofungin decrease, and are about 30% lower than in patients not receiving
rifampicin. Antifungal treatment failure has been seen in a patient taking
rifampicin with
caspofungin 70 mg daily.
The manufacturers say that consideration should be given to increasing the dose of
caspofungin from 50 to 70 mg daily in patients taking enzyme-inducing drugs. However, close monitoring is still required because of the isolated report of treatment failure even at the higher dose.